The embodiments described herein relate generally to an arc chute assembly for a circuit breaker, and more particularly, to methods and systems used to distribute gas pressure formed within a circuit breaker.
The capability of circuit breakers for current-interruption can be dependent, in part, upon the ability to extinguish the arc that is generated when the breaker contacts open. Even though the contacts separate, current can continue to flow through the ionized gases formed by vaporization of the contacts and surrounding materials. Circuit breakers require expedient and efficient cooling of the arc to facilitate effective current interruption. Circuit breakers include sub-poles that are located in arc chutes. The arc chutes are configured to extinguish the arc that is produced when the breaker is tripped and the contacts of the breaker are rapidly opened. Typically, each arc chute is associated with a single phase, for example, one phase of a 3-phase power distribution system.
Conventional arc chutes include a series of metallic plates that are configured in a spaced apart relationship and held in place by dielectric side panels. When the contacts of the breaker are opened, the resulting arc is driven to the metallic plates of the arc chute where the arc is then extinguished by the plates. The metallic plates increase the arc voltage in the circuit breaker to produce a current-limiting effect thereby providing downstream protection.
Each sub-pole for the current path of the circuit breaker includes an arc chute. The sub-poles are electrically connected in parallel and separated inside the circuit breaker by a divider wall. Due to component variations, one sub-pole may experience a higher pressure than the other sub-pole when the breaker is tripped. While increasing the volume of gas generated during current-interruption and enhancing current flow aids in extinguishing the arc, the increased volume of gas increases pressure within the sub-poles, and therefore, on the arc chute and the circuit breaker housing. In some cases, the sub-pole that is exposed to the higher pressure may experience damage to the housing walls and the arc chute which may limit the current-interruption capability of the circuit breaker.